An internal combustion engine has a humidity sensor that is disposed in an intake passage of the internal combustion engine, a temperature sensor configured to detect an intake air temperature in a position of the humidity sensor, and a controller configured to correct an offset error of the sensor value by adding a correction value to the sensor value. The controller is configured to acquire the intake air temperatures respectively at a plurality of timings in a process of the intake air temperature changing, acquire the sensor values at the respective plurality of timings, calculate values excluding influences of temperature differences of the intake air temperatures from the respective sensor values as humidity index values respectively, and determine a correction value so that a variation degree of the humidity index values becomes small.

An exhaust system for a combustion engine includes first and second catalytic converters arranged downstream of the combustion engine in a flow direction of exhaust gas. First and second exhaust pipes extend from the combustion engine to the first and second catalytic converters, respectively, with a first valve disposed in the first exhaust pipe, and a second valve disposed in the second exhaust pipe. The first and second valves operate such that in the presence of an exhaust temperature which is equal to or less than a limit value, at least the first valve opens to allow exhaust gas from the combustion engine to flow through the first catalytic converter, and that the first valve closes and the second valve opens, when the exhaust temperature is greater than the limit value to thereby allow exhaust gas from the combustion engine to flow through the second catalytic converter.

An exhaust gas carbon dioxide capture and recovery system that may be mounted on a mobile vehicle or vessel. The system may include an exhaust absorber system, a solvent regenerator, a solvent loop, a carbon dioxide compressor, and a carbon dioxide storage tank, among other components. The system may be configured and integrated such that energy in the exhaust may be used to power and drive the carbon dioxide capture while having minimal parasitic effect on the engine.

Systems and methods described herein relate to generating ammonia from engine exhaust instead of or in addition to using on-board storage tank(s) and/or doser(s) to provide the necessary chemical reagents for purification of the exhaust stream. Systems and methods for generating ammonia and/or hydrogen from engine exhaust in exhaust aftertreatment systems under ambient conditions comprise at least one water-gas shift (WGS) catalyst and at least one ammonia synthesis catalyst (AMS catalyst) positioned downstream of the WGS catalyst. The WGS catalyst is configured, using the engine exhaust gas as an input, to generate hydrogen used by the AMS catalyst as inputs to generate ammonia and/or hydrogen. The ammonia and/or hydrogen thus generated are used downstream in ammonia- and/or hydrogen-based selective catalytic reduction catalysts (SCR).

An engine system includes: an engine including a plurality of combustion chambers generating driving torque by combustion of fuel; an exhaust gas purification apparatus installed at an exhaust line in which exhaust gas exhausted from the combustion chambers flows; a bypass line branched from the exhaust line at an upstream side of the exhaust gas purification apparatus and joining the exhaust line at a downstream side of the exhaust gas purification apparatus so that the exhaust gas flowing in the exhaust line bypasses the exhaust gas purification apparatus; and a bypass valve installed at the bypass line.

A reagent dosing system for dosing a reagent into the exhaust gas stream of an internal combustion engine includes a reagent tank for storing a supply of reagent; an injector module including an atomizing dispenser and a positive-displacement metering pump which draws reagent from the reagent tank and delivers it to the dispenser; a supply line coupling the reagent tank to the injector module; a dosing control unit operable to control the injector module to inject reagent into the exhaust gas stream; and an additional priming pump arranged, in use, to urge reagent along the supply line toward the injector module under selected conditions.

An exhaust gas carbon dioxide capture and recovery system that may be mounted on a mobile vehicle or vessel. The system may include an exhaust absorber system, a solvent regenerator, a solvent loop, a carbon dioxide compressor, and a carbon dioxide storage tank, among other components. The system may be configured and integrated such that energy in the exhaust may be used to power and drive the carbon dioxide capture while having minimal parasitic effect on the engine.

A method for controlling the operation of an exhaust aftertreatment system (EATS) in a vehicle is described. The EATS comprises a main SCR catalyst and a pre-SCR catalyst, a pre-injector arranged upstream the pre-SCR catalyst for providing reductant, a bypass channel fluidly connected to the fluid channel and arranged to bypass the pre-SCR-catalyst and the pre-injector, and a valve configured to control a split of exhaust gases between the pre-SCR catalyst and the bypass channel. The method includes determining the amount of ammonia stored in the pre-SCR catalyst; determining the temperature of the main SCR catalyst; when the ammonia storage in the pre-SCR catalyst is below an ammonia storage threshold and the temperature of the main SCR catalyst is above a temperature threshold, injecting reductant by the pre-injector and controlling the valve to allow a flow of exhaust gases to the pre-SCR catalyst sufficient for transporting the injected reductant to the pre-SCR catalyst for increasing the ammonia storage.

An exhaust emission control system of an engine including a NO.sub.x catalyst for storing NO.sub.x within exhaust gas when an air-fuel ratio thereof is lean, and reducing the NO.sub.x when the air-fuel ratio is approximately stoichiometric or rich, the NO.sub.x catalyst also functioning as an oxidation catalyst for oxidizing HC, is provided. The system includes a SCR catalyst for purifying NO.sub.x by causing a reaction with NH.sub.3, a urea injector, and a processor configured to execute a fuel injection controlling module, and a NO.sub.x reduction controlling module for performing a NO.sub.x reduction control to enrich the air-fuel ratio to a target ratio. When the urea injection is abnormal, the NO.sub.x reduction controlling module performs an NH.sub.3-supplied NO.sub.x reduction control in which the NO.sub.x catalyst supplies NH.sub.3 to the SCR catalyst, by performing the NO.sub.x reduction control, a lean air-fuel ratio operation control, and then the NO.sub.x reduction control again.

An exhaust gas carbon dioxide capture and recovery system that may be mounted on a mobile vehicle or vessel. The system may include an exhaust absorber system, a solvent regenerator, a solvent loop, a carbon dioxide compressor, and a carbon dioxide storage tank, among other components. The system may be configured and integrated such that energy in the exhaust may be used to power and drive the carbon dioxide capture while having minimal parasitic effect on the engine.